Pulp Regeneration by Harnessing Dental Pulp Stem Cells - New Trends in Tissue Engineering and Regenerative Medicine - page 41

formation and mechanical properties after hardening in vivo. In addition the scaffold has to
be biocompatible, with high bioactivity to integrate trophic factors secreted by stem cells.
Furthermore it should be biodegradable by releasing these factors to replace the damaged
tissue by newly regenerated tissue without immune response. In addition, the scaffold should
not stimulate mineralization and differentiation of odontoblasts and/or osteodentinoblasts in
the root canal except along the dentinal wall for pulp regeneration (Nakashima, et al., 2009).
Potential scaffolds include natural polymers, such as collagen and gelatin with good biocom‐
patibility and bioactivity (Nakashima and Akamine, 2005).
Figure 3. Complete pulp regeneration after autologous transplantation of CD105 + cells with SDF-1 in the pulpectom‐
ized root canal in dogs. (A-F) CD105 + cells with SDF-1. (C) Three dimensional images of new vascularization by whole
mount immunostaining with lectin. (D) DiI-labeling from the upper part of the regenerated pulp on day 14. Note infe‐
rior alveolar nerve connecting to the regenerated pulp, suggesting re-innervation. (F) Odontoblastic cells (arrows) lin‐
ing to newly formed osteodentin/tubular dentin (OD) along with the dentinal wall. (G) CD105 + cells only. (H) SDF-1
only. (I) Total pulp cells with SDF-1. Mineralized tissue (arrow) and osteodentin. (Iohara et al., Tissue Eng. 2011)
Thus, based on the concepts described above, pulp regeneration has been demonstrated by
using the triad, stem/progenitor cells, migration/homing factors and optimal scaffolds
(Nakashima, et al., 2011, Iohara, et al., 2011)(Figure 1B). Pulpectomy with enlarged apical
portion, 0.6~0.7 mm in width, was performed in mature teeth with complete apical closure in
an experimental model in dogs (Iohara, et al., 2011, Ishizaka et al., 2012). Current evidence
shows that the root canal is filled with pulp-like loose connective tissue with vasculature and
nerves after autologous transplantation of pulp stem/progenitor cells, CD31 - SP cells or pulp
CD105 + cells, 5×10 5 cells in cell number, with SDF-1 in collagen type I and type III scaffold
(Figure 3A-F) (Nakashima, et al., 2011, Iohara, et al., 2011, Ishizaka et al., 2012). The three
dimensional image of induced vascularization in the regenerated tissue (Figure 3C) is similar
in density and orientation to those in the normal pulp. The neuronal process from regenerated